Method and apparatus for identifying patients with wide QRS complexes

ABSTRACT

A medical device programmer or other external system capable of programming an implantable CRM device includes a wide-QRS detection and alerting system. Upon detection of a wide QRS complex, a wide-QRS indicator produces a visual indication of the detection using one or more presentation devices such as a display screen and a printer to alert a physician or other caregiver.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/055,731, filed Feb. 10, 2005, which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

This document generally relates to cardiac rhythm management (CRM)systems and particularly, but not by way of limitation, to such a systemthat identifies patients with wide QRS complexes.

BACKGROUND

The heart is the center of a person's circulatory system. The leftportions of the heart, including the left atrium (LA) and left ventricle(LV), draw oxygenated blood from the lungs and pump it to the organs ofthe body to provide the organs with their metabolic needs for oxygen.The right portions of the heart, including the right atrium (RA) andright ventricle (RV), draw deoxygenated blood from the body organs andpump it to the lungs where the blood gets oxygenated. These mechanicalpumping functions are accomplished by contractions of the heart. In anormal heart, the sinoatrial (SA) node, the heart's natural pacemaker,generates electrical impulses, called action potentials, that propagatethrough an electrical conduction system to various regions of the heartto cause the muscular tissues of these regions to depolarize andcontract at a normal sinus rate.

Electrocardiography (ECG) is known to indicate the functions of theelectrical conduction system by monitoring the action potentials atvarious portions of the heart. A QRS complex is a segment of an ECGsignal that indicates depolarization of the ventricles. An abnormallywide QRS complex is an indication that the conduction of the electricalimpulses through the ventricles is prolonged. The prolonged conductionmay result from conditions related to heart failure, includinghypertrophy or dilatation of one or both ventricles and/or blockage ofthe Purkinje fibers that conduct the electrical impulses in theventricles. Thus, physicians and other caregivers use the width of theQRS complex as an indication of abnormal cardiac conditions, includingheart failure, that may need medical treatments.

Implantable CRM devices such as pacemakers and defibrillators are usedto treat cardiac arrhythmias, heart failure, and other cardiovasculardisorders by delivering electrical energy to the heart. An abnormallywide QRS complex is one of the factors that prompt a physician or othercaregiver to consider an application or adjustment of a cardiacelectrical therapy using an implantable CRM device.

For these and other reasons, there is a need for an easy and convenientway to detect wide QRS complexes and, if detected, communicate theresult to a physician or other caregiver for consideration of applyingor adjusting the cardiac electrical therapy.

SUMMARY

A medical device programmer or other external system capable ofprogramming an implantable CRM device includes a wide-QRS detection andalerting system. Upon detection of a wide QRS complex, a wide-QRSindicator produces a visual indication of the detection using one ormore presentation devices such as a display screen and a printer toalert a physician or other caregiver.

In one embodiment, a CRM system includes an implantable medical deviceand an external system communicatively coupled to the implantablemedical device via telemetry. The implantable medical device includes apacing circuit to deliver pacing pulses and an implant controller tocontrol the delivery of the pacing pulses. The external system includesa user interface, a programming circuit, and a wide-QRS detection andalerting circuit. The user interface includes one or more user inputdevices and one or more presentation devices. The programming circuitallows for programming of the implantable medical device. The wide-QRSdetection and alerting circuit includes a wide-QRS detector and awide-QRS indicator. The wide-QRS detector receives an ECG signal anddetects a wide QRS complex from the ECG signal. The wide-QRS indicatorproduces a wide-QRS indication using the one or more presentationdevices when the wide QRS complex is detected.

In one embodiment, a medical device programmer includes an externaltelemetry circuit, a user interface, a programming circuit, a surfaceECG sensing circuit, and a wide-QRS detection and alerting circuit. Theexternal telemetry circuit allows the medical device programmer tocommunicate with an implantable medical device. The user interfaceincludes one or more user input devices and one or more presentationdevices. The programming circuit allows for the programming of theimplantable medical device. The surface ECG sensing circuit senses atleast one surface ECG signal. The wide-QRS detection and alertingcircuit includes a wide-QRS detector and a wide-QRS indicator. Thewide-QRS detector receives the surface ECG signal and detects a wide QRScomplex from the surface ECG signal. The wide-QRS indicator produces awide-QRS indication using the one or more presentation devices when thewide QRS complex is detected.

In one embodiment, an external system communicates with an implantablemedical device coupled to implantable electrodes. The external systemincludes an external telemetry circuit, a programming circuit, a userinterface, and a wide-QRS detection and alerting circuit. The externaltelemetry circuit receives at least one wireless ECG signal from theimplantable medical device. The wireless ECG signal is a signal sensedthrough the implantable electrodes and approximating a surface ECGsignal. The programming circuit allows for programming of theimplantable medical device. The user interface includes one or morepresentation devices. The wide-QRS detection and alerting circuitincludes a wide-QRS detector and a wide-QRS indicator. The wide-QRSdetector receives the wireless ECG signal and detects a wide QRS complexfrom the wireless ECG signal. The wide-QRS indicator produces a wide-QRSindication using the one or more presentation devices when the wide QRScomplex is detected.

In one embodiment, a method is provided for operating a medical deviceprogrammer communicating with an implantable medical device. A surfaceECG signal is sensed by using a surface ECG sensing circuit of themedical device programmer. A QRS width is measured from the surface ECGsignal. A wide QRS complex is detected by comparing the measured QRSwidth to a predetermined threshold QRS width. When the QRS width exceedsthe predetermined threshold QRS width, a visual indication of adetection of the wide QRS complex is presented using a presentationdevice of the medical device programmer.

In one embodiment, a method is provided for operating an external systemcommunicating with an implantable medical device coupled to implantableelectrodes. A wireless ECG signal is received from the implantablemedical device. The wireless ECG is a signal sensed through theimplantable electrodes and approximating a surface ECG. A QRS width ismeasured from the wireless ECG signal. A wide QRS complex is detected bycomparing the QRS width to a predetermined threshold QRS width. When theQRS width exceeds the predetermined threshold QRS width, a visualindication of a detection of the wide QRS complex is presented using apresentation device of the external system.

This Summary is an overview of some of the teachings of the presentapplication and not intended to be an exclusive or exhaustive treatmentof the present subject matter. Further details about the present subjectmatter are found in the detailed description and appended claims. Otheraspects of the invention will be apparent to persons skilled in the artupon reading and understanding the following detailed description andviewing the drawings that form a part thereof, each of which are not tobe taken in a limiting sense. The scope of the present invention isdefined by the appended claims and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are for illustrative purposes only and notnecessarily drawn to scale, like numerals describe similar componentsthroughout the several views. The drawings illustrate generally, by wayof example, but not by way of limitation, various embodiments discussedin the present document.

FIG. 1 is an illustration of an embodiment of a CRM system and portionsof an environment in which the CRM system is used.

FIG. 2 is a block diagram illustrating an embodiment of a circuit of theCRM system.

FIG. 3 is a block diagram illustrating an embodiment of a user interfaceof the CRM system.

FIG. 4 is a block diagram illustrating an embodiment of a wide-QRSdetection and alerting circuit of the CRM system.

FIG. 5 is an illustration of an embodiment of the CRM system includingan external patient management system and portions of the environment inwhich the CRM system is used.

FIG. 6 is a flow chart illustrating one embodiment of a method fordetecting and indicating wide QRS complexes using a medical deviceprogrammer.

FIG. 7 is a flow chart illustrating one embodiment of a method fordetecting and indicating wide QRS complexes based on a wireless ECGsignal sensed by an implantable medical device.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that the embodiments may be combined, or that otherembodiments may be utilized and that structural, logical and electricalchanges may be made without departing from the spirit and scope of thepresent invention. The following detailed description provides examples,and the scope of the present invention is defined by the appended claimsand their equivalents.

It should be noted that references to “an”, “one”, or “various”embodiments in this document are not necessarily to the same embodiment,and such references contemplate more than one embodiment. In thisdocument, “electrogram” or “intracardiac electrogram” refers to acardiac electrical signal sensed with one or more implantable sensingelectrodes placed in or on the heart. “Surface ECG” refers to a cardiacelectrical signal sensed with electrodes attached onto the exteriorsurface of the skin. “Wireless ECG” refers to a signal approximating thesurface ECG, acquired without using surface (non-implantable, skincontact) electrodes. “Subcutaneous ECG” is a form of wireless ECG andincludes a cardiac electrical signal sensed through electrodes implantedin subcutaneous tissue, such as through electrodes incorporated onto animplantable medical device that is subcutaneously implanted. A surfaceECG is morphologically different from an intracardiac electrogrambecause of the difference in the sources that produce these signals. Asreflected in their corresponding morphologies, the surface ECG resultsfrom electrical activities of the entire heart, while the intracardiacelectrogram primarily results from the spread of electrical activity ina region in close proximity to the one or more implantable sensingelectrodes placed in or on the heart. The wireless ECG, including butnot being limited to the subcutaneous ECG, has a morphology thatapproximates that of the surface ECG and reflects electrical activitiesof a substantial portion of the heart, up to the entire heart.

This document discusses, among other things, a CRM system thatautomatically identifies patients with wide QRS complexes. A wide QRScomplex is a QRS complex having a width that exceeds a threshold QRSwidth. The CRM system includes an implantable medical device and amedical device programmer or other external system communicating withthe implantable medical device. When a wide QRS complex is detected, themedical device programmer or other external system provides a physicianor other caregiver with a conspicuous visual indication using one ormore presentation devices such as a display screen and a printer.

FIG. 1 is an illustration of one embodiment of a CRM system 100 andportions of the environment in which CRM system 100 is used. System 100includes an implantable medical device 110, a lead system 108, anexternal system 130, a wireless telemetry link 125, surface ECGelectrodes 106A-D, and an ECG lead cable 107.

After implantation, implantable medical device 110 operates within abody 102 to sense activities of a heart 105 and deliver one or moretherapies to heart 105. Implantable medical device 110 includes, but isnot limited to, one or more of a pacemaker, acardioverter/defibrillator, a cardiac resynchronization therapy (CRT)device, a cardiac remodeling control therapy (RCT) device, a drugdelivery device, and a biological therapy device.

Lead system 108 provides one or more electrical and/or other connectionsbetween implantable medical device 110 and heart 105. In one embodiment,lead system 108 includes one or more pacing and/or defibrillation leadseach having one or more electrodes for sensing cardiac electricalsignals and/or delivering electrical pulses to heart 105. In oneembodiment, one or more intracardiac sensors are incorporated into leadsystem 108 to sense signals such as heart sounds, intracardiacpressures, and chemical parameters of the blood.

In one embodiment, implantable medical device 110 is capable of sensingone or more wireless ECG signals and transmitting them to externaldevice 130. The one or more wireless ECG signals are sensed usingelectrodes incorporated into lead system 108 and/or electrodesincorporated onto implantable medical device 110. In one specificembodiment, the one or more wireless ECG signals include one or moresubcutaneous ECG signals sensed through implantable subcutaneouselectrodes.

External system 130 communicates with implantable medical device 110through telemetry link 125. External system 130 allows a physician orother caregiver to communicate with implantable medical device 110.External system 130 includes a programming circuit 140, a wide-QRSdetection and alerting circuit 160, and a user-interface 180.Programming circuit 140 allows the physician or other caregiver toprogram implantable medical device 110. Wide-QRS detection and alertingcircuit 160 detects a wide QRS complex, i.e., a QRS complex having awidth or duration that is longer than a predetermined threshold, from anECG signal indicative of cardiac electrical activities of heart 105 andproduces a visual indication of each detection of a wide QRS complex forpresentation on user interface 180. In one embodiment, the ECG signal isa wireless ECG signal sensed by implantable medical device 110. Inanother embodiment, the ECG signal is sensed through surface electrodes106A-D, which are connected to external system 130 through an ECG leadcable 107.

In one embodiment, external system 130 includes an external medicaldevice programmer. The medical device programmer includes programmingcircuit 140, the wide-QRS detection and alerting circuit 160, and userinterface 180. In another embodiment, external system 130 is a patientmanagement system including an external device, a telecommunicationnetwork, and a remote device. The external device is placed within thevicinity of implantable medical device 110 and communicates withimplantable medical device 110 bi-directionally via telemetry link 125.The remote device is in a remote location and communicates with theexternal device bi-directionally through the telecommunication network,thus allowing a physician or other caregiver to monitor and treat apatient from a distant location. In one embodiment, the remote deviceincludes at least portions of programming circuit 140, the wide-QRSdetection and alerting circuit 160, and user interface 180.

Telemetry link 125 provides for communication between implantablemedical device 110 and external system 130. In one embodiment, telemetrylink 125 is an inductive telemetry link. In an alternative embodiment,telemetry link 125 is a far-field radio-frequency telemetry link.Telemetry link 125 provides for data transmission from implantablemedical device 110 to external system 130. This may include, forexample, transmitting information indicative of the device type ofimplantable medical device 110, transmitting data indicative of thecurrent operational mode(s) and parameter values, transmitting real-timephysiological data acquired by implantable medical device 110,extracting physiological data acquired by and stored in implantablemedical device 110, extracting therapy history data, and extracting dataindicating an operational status (e.g., battery status and leadimpedance). Telemetry link 125 also provides for data transmission fromexternal system 130 to implantable medical device 110. This may include,for example, parameters for programming implantable medical device 110to acquire physiological data, to perform at least one self-diagnostictest (such as for a battery status and lead impedance status), and/or todeliver at least one therapy. The physiological data represent signalsacquired by implantable medical device 110. The signals include, but arenot limited to, one or more of electrograms, wireless ECG signals, heartsounds or signals indicative of heart sounds, activity level signals,impedance signals, pressure or pressure-indicating signals, andrespiratory signals. In one embodiment, the physiological data alsoinclude parameters measured from one or more of these signals. In oneembodiment, external system 130 or the physician or other caregiverdetermines parameter values for programming implantable medical device110 based on these physiological data.

FIG. 2 is a block diagram illustrating an embodiment of a circuit of aCRM system 200. CRM system 200 represents one embodiment of CRM system100 and includes an implantable medical device 210 coupled toimplantable ECG electrodes 209 and lead system 108, an external system230 coupled to surface ECG electrodes 206, and wireless telemetry link125. As illustrate in FIG. 2, CRM system 200 is capable of detectingwide QRS complexes from either a wireless ECG signal sensed byimplantable medical device 210 through implantable ECG electrodes 209 ora surface ECG signal sensed by external system 230 through surface ECGelectrodes 206. In various specific embodiments, CRM system 200 detectswide QRS complexes from the wireless ECG signal, the surface ECG signal,or both.

Implantable medical device 210 is a specific embodiment of implantablemedical device 110 and includes a pacing circuit 212, an electrogramsensing circuit 214, a wireless ECG sensing circuit 216, an implantcontroller 218, and an implant telemetry circuit 224. Pacing circuit 212delivers pacing pulses to the heart. In one embodiment, implantablemedical device 210 includes one or more additional therapy deliverydevices such as a cardioversion/defibrillation circuit to delivercardioversion/defibrillation pulses, a substance delivery device todeliver chemical and/or biological agents, and a biological therapydevice to deliver signals controlling a gene therapy. Electrogramsensing circuit 214 senses one or more electrograms. Wireless ECGsensing circuit 216 senses one or more wireless ECG signals throughimplantable ECG electrodes 209. Implantable ECG electrodes 209 includeintracardiac electrodes, epicardial electrodes, subcutaneous electrodes,or any combination of such electrodes. In one embodiment, implantableECG electrodes 209 include subcutaneous electrodes that are incorporatedonto implantable medical device 210. Examples of a circuit andimplantable electrodes for sensing the wireless ECG is discussed in U.S.patent application Ser. No. 10/795,126, entitled “WIRELESS ECG INIMPLANTABLE DEVICES,” filed on Mar. 5, 2004, assigned to CardiacPacemakers, Inc., which is incorporated herein by reference in itsentirety. Implant controller 218 controls the sensing of theelectrograms and wireless ECG signals and the delivery of pacing pulsesand/or other therapies. In one embodiment, implantable controller 218includes a CRT algorithm execution module 220 that controls the deliveryof pacing pulses by executing a CRT algorithm. The CRT pacing algorithmis executed with one or more pacing parameters approximately optimizedto maximize a measure of hemodynamic performance. Implant telemetrycircuit 224 provides implantable medical device 210 with the telemetrycapability required for communicating with external device 230 viatelemetry link 125.

External system 230 is a specific embodiment of external system 130 andincludes an external telemetry circuit 226, a programming circuit 240, asurface ECG sensing circuit 234, a wide-QRS detection and alertingcircuit 260, and a user interface 280. External telemetry circuit 226provides external system 230 with the telemetry capability required forcommunicating with implantable medical device 210 via telemetry link125. Programming circuit 240 programs implantable medical device 210 byproducing programming instructions based on user input received throughuser interface 280. External telemetry circuit 226 receives theseprogramming instructions and transmits them to implantable medicaldevice 210. In one embodiment, external telemetry circuit 226 receivesone or more wireless ECG signals from implantable medical device 210.Surface ECG sensing circuit 234 senses one or more surface ECG signalsusing surface ECG electrodes 206. Wide-QRS detection and alertingcircuit 260 includes a wide QRS detector 262 and a wide-QRS indicator264. Wide QRS detector 262 receives an ECG signal and detects wide QRScomplexes from the ECG signal. In one embodiment, the ECG signal is asurface ECG signal received from surface ECG sensing circuit 234. Inanother embodiment, the ECG signal is a wireless ECG signal receivedfrom external telemetry circuit 226, which receives that wireless ECGsignal from implantable medical device 210. Wide QRS detector 262detects the wide QRS complexes by detecting QRS complexes, measuring thewidth of each QRS complex, and comparing the width to a predeterminedthreshold QRS width. When a wide QRS complex is detected, wide-QRSindicator 264 produces a wide-QRS indication for presentation using userinterface 280. Additional details of wide-QRS detection and alertingcircuit 260 are discussed below with reference to FIG. 4. User interface280 includes one or more user input devices 282 and one or morepresentation devices 284. User input device(s) 282 allow the physicianor other caregiver to control the operation of implantable medicaldevice 210, and to control the operation of external system 230including wide-QRS detection and alerting circuit 260. Presentationdevice(s) 282 displays and/or prints information related to thepatient's physiological activities and conditions, including thewide-QRS indication and information related to the operation ofimplantable medical device 210. Additional details of user interface 280are discussed below with reference to FIG. 3.

FIG. 3 is a block diagram illustrating an embodiment of a user interface380. User interface 380 is a specific embodiment of user interface 280and includes user input devices 382 and presentation devices 384. Userinput devices 382 includes a programming input device 386 and athreshold input device 387. Programming input device 386 receives userinputs related to the programming of implantable medical device 210,such as therapy commands and parameters, from the physician or othercaregiver and sends the user inputs to programming circuit 240.Threshold input device 387 receives the threshold QRS width from thephysician or other caregiver and sends the threshold QRS width towide-QRS detector 262. In one embodiment, threshold input device 387allows the physician or other caregiver to type in the threshold QRSwidth. In another embodiment, threshold input device 387 allows thephysician or other caregiver to select from a plurality of predeterminedthreshold QRS widths. Presentation devices 384 include a screen 388 anda printer 389. In response to a wide-QRS indication produced by wide-QRSindicator 264, an alert message indicating a wide QRS complex isdisplayed on screen 388 and/or printed by printer 389. In oneembodiment, presentation devices 384 further include a speaker toproduce an audio tune to attract attention from the physician or othercaregiver to the detection of the wide QRS complex.

FIG. 4 is a block diagram illustrating an embodiment of a wide-QRSdetection and alerting circuit 460. Wide-QRS detection and alertingcircuit 460 is a specific embodiment of wide-QRS detection and alertingcircuit 260 and includes a wide-QRS detector 462 and a wide-QRSindicator 464. In one embodiment, wide-QRS detection and alertingcircuit 460 detects wide QRS complexes from a surface ECG signal. Inanother embodiment, wide-QRS detection and alerting circuit 460 detectswide QRS complexes from a wireless ECG signal. In another embodiment,wide-QRS detection and alerting circuit 460 is selectively programmablefor detecting wide QRS complexes from one of a surface ECG and awireless ECG.

Wide-QRS detector 462 is a specific embodiment of wide-QRS detector 262and includes a signal input 466, a QRS width measurement module 467, anda QRS width comparator 468. Signal input 466 receives an ECG signal fromwhich wide QRS complexes are to be detected. In one embodiment, signalinput 466 receives a surface ECG signal from surface ECG sensing circuit234. In another embodiment, signal input 466 receives a wireless ECGsignal from external telemetry circuit 226. In another embodiment,signal input 466 is programmable for either receiving the surface ECGsignal from surface ECG sensing circuit 234 or receiving the wirelessECG signal from external telemetry circuit 226. QRS width measurementmodule 467 measures the QRS width from the ECG signal received by signalinput 466. In one embodiment, QRS width measurement module 467 includesa peak detector and a deviation detector. The peak detector detectsR-wave peaks. The deviation detector detects points on the ECG signalwhere the amplitude deviates from its baseline value. Upon detection ofan R-wave peak, QRS width measurement module 467 measures the timeinterval between two adjacent deviation points detected before and afterthe R-wave peak. This time interval is the QRS width. In one embodiment,to measure a QRS width, the peak detector detects an R-wave peak, andthe deviation detector detects the deviation points by assessing aseries of digitized points of the ECG signal before and after the R-wavepeak to determine when the ECG signal deviates from the baseline by apredetermined percentage, such as approximately 10%. The deviationpoints include two points, one before the R-wave peak and one after theR-wave peak, that are the points closest to the R-wave peak and wherethe ECG signal deviates from the baseline by the predeterminedpercentage. In one specific embodiment, the percentage is programmable.The QRS width equals the sampling rate multiplied by the number of thedigitized points (samples) between the two deviation points. In afurther embodiment, QRS width measurement module 467 measures the QRSwidth when the R-wave peaks are detected at a rate between approximately30 beats per minute to 300 beats per minute, which corresponding to arate interval of 200 milliseconds to 2 seconds. QRS width comparator 468has a first input, a second input, and an output. The first input of QRSwidth comparator 468 receives the QRS width from QRS width measurementmodule 467. The second input of QRS width comparator 468 receives apredetermined threshold QRS width. In one embodiment, the second inputreceives a predetermined threshold QRS width from threshold input device387. In another embodiment, the predetermined threshold QRS width is abuilt-in or default value stored in a storage circuit of external system230. In one embodiment, the built-in or default values is used unlessand until the physician or caregiver changes it using threshold inputdevice 387. In one embodiment, the built-in or default value is about120 milliseconds. The output of QRS width comparator 468 indicates adetection of the wide QRS complex when the QRS width exceeds thepredetermined threshold QRS width.

Wide-QRS indicator 464 is a specific embodiment of wide-QRS indicator264 and includes an image generator 470 and a message generator 471.Image generator 470 produces a visual indication of the detection of thewide QRS complex to present on screen 388. In one embodiment, upondetection of the wide QRS complex, image generator 470 causes a messagewindow to pop up on screen 388. The window displays a conspicuousmessage such as “Wide QRS Complex” or “Attention: Wide QRS.” In afurther embodiment, image generator 470 also causes the measured QRSwidth to be displayed in the message window. Message generator 471produces a message indicative of the detection of the wide QRS complexto print by printer 389. In one embodiment, the message includes aconspicuously printed header such as “Wide QRS Complex” or “Attention:Wide QRS” followed by the measured QRS width.

In one embodiment, external system 230 includes a medical deviceprogrammer. In a specific embodiment, the medical device programmerdetects the wide QRS complex from the surface ECG signal. Theimplantable medical device communicating with the medical deviceprogrammer does not necessarily sense a wireless ECG. In anotherspecific embodiment, the medical device programmer detects the wide QRScomplex from the wireless ECG signal. When the medical device programmercommunicates with an implantable medical device that senses a wirelessECG, there is no need to attach surface ECG electrodes and connectingthe surface ECG electrodes to the medical device programmer using an ECGlead cable. In another specific embodiment, as illustrated in FIG. 2,the medical device programmer is capable of detecting QRS width fromeither the surface ECG signal or the wireless ECG signal. One of thesurface ECG signal and the wireless ECG signal is selected for detectingwide QRS complexes based on whether the wireless ECG signal is availableand/or the quality of each available ECG signal.

In another embodiment, external system 230 is a patient monitoringsystem that is illustrated in FIG. 5 as external system 530. FIG. 5 isan illustration of an embodiment of a CRM system 500 and portions of anenvironment in which CRM system 500 is used. CRM system 500 is aspecific embodiment of CRM system 100. External system 530 includes anexternal device 590, a remote device 594, and a telecommunicationnetwork 592 coupled between external device 590 and remote device 594.In one embodiment, external system 530 includes the elements of external230 as illustrated in FIG. 2 except for surface ECG sensing circuit. Thedistribution of the elements in external system 530 depends on designand patient management considerations. In one exemplary embodiment,external device 590 includes at least external telemetry circuit 226 toreceive the wireless ECG signal from implantable medical device 210.Remote device 594 includes at least wide-QRS indicator 264 andpresentation device(s) 284. Upon detection of the wide QRS complex,remote device 592 informs the physician or other caregiver in a locationremote from the patient. This allows prompt medical attention, forexample, when the patient's cardiac condition worsens. In oneembodiment, upon detection of the wide QRS complex, external system 530programs implantable medical device 210 to adjust a therapy, such as tostart delivering pacing pulses by executing the CRT algorithm.

FIG. 6 is a flow chart illustrating one embodiment of a method fordetecting and indicating wide QRS complexes using a medical deviceprogrammer communicating with an implantable medical device. A surfaceECG is sensed, at 600, using a surface ECG sensing circuit of themedical device programmer. A QRS width is measured from the surface ECGsignal at 610. A wide QRS complex is detected by comparing the QRS widthto a predetermined threshold QRS width at 620. When the QRS widthexceeds the predetermined threshold QRS width, a visual indication of adetection of the wide QRS complex is presented, at 630, using apresentation device of the medical device programmer. In one embodiment,the visual indication of the detection of the wide QRS complex ispresented on a display screen of the medical device programmer. Inanother embodiment, a message indicative of the detection of the wideQRS complex is printed using a printer of the medical device programmer.

In one embodiment, the predetermined threshold QRS width is stored inthe medical device programmer. In a further embodiment, the storethreshold QRS threshold is a default value that is changed when anotherthreshold QRS width is received through a user input device of themedical device programmer.

In one embodiment, the implantable medical device is programmed toadjust a therapy delivery, and the QRS width is measured after thetherapy delivery is adjusted. For example, to detect wide QRS complexesbased on intrinsic (non-paced) QRS widths of a patient receiving apacing therapy, the physician or other caregiver programs theimplantable medical device to stop the delivery of the pacing therapyusing the medical device programmer. To evaluate the effect of pacing orone or more pacing parameters in the QRS width, the physician or othercaregiver programs the implantable medical device to start the deliveryof the pacing therapy and/or to adjust one or more pacing parametersusing the medical device programmer.

FIG. 7 is a flow chart illustrating one embodiment of a method fordetecting and indicating wide QRS complexes based on a wireless ECGsignal sensed by an implantable medical device. The wireless ECG signalis received from the implantable medical device at 700. In oneembodiment, the wireless ECG is a subcutaneous ECG signal sensed throughsubcutaneous electrodes attached to the implantable medical device. AQRS width is measured from the wireless ECG signal at 710. A wide QRScomplex is detected, at 720, by comparing the QRS width to apredetermined threshold QRS width. When the QRS width exceeds thepredetermined threshold QRS width, a visual indication of a detection ofthe wide QRS complex is presented, at 730, using a presentation deviceof an external system communicating with the implantable medical device.In one embodiment, the visual indication of the detection of the wideQRS complex is presented on a display screen of the external system. Inanother embodiment, a message indicative of the detection of the wideQRS complex is presented using a printer of the external system.

In one embodiment, the predetermined threshold QRS width is pre-stored.In a further embodiment, the pre-stored threshold QRS threshold is adefault value that is changed when another threshold QRS width isentered by the physician or other caregiver.

In one embodiment, the detection of the wide QRS complex is indicated tothe physician or other caregiver at a location remote from the patient.The physician or other caregiver determines the need to start, stop, oradjust a therapy delivery, such as based on additional informationacquired by the implantable medical device and transmitted to the remotelocation through the external system. In a further embodiment, theexternal system starts, stops, or adjusts a therapy delivery based onthe information received from the implantable medical device. In oneembodiment, in response to the detection of the wide QRS complex, theimplantable medical device is programmed to adjust therapy parameters.

It is to be understood that the above detailed description is intendedto be illustrative, and not restrictive. Other embodiments, includingany possible permutation of the system components discussed in thisdocument, will be apparent to those of skill in the art upon reading andunderstanding the above description. The scope of the invention should,therefore, be determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled.

1. An external system configured to be communicatively coupled to an implantable medical device, the external system comprising: an external telemetry circuit configured to communicate with the implantable medical device; a user interface coupled to the external telemetry circuit, the user interface including a screen; and a wide-QRS detection and alerting circuit coupled to the user interface, the wide-QRS detection and alerting circuit including: a wide-QRS detector including a signal input to receive an electrocardiogram (ECG) signal, a QRS width measurement module configured to measure the QRS width using the received ECG signal, and a QRS width comparator having a first input to receive the measured QRS width, a second input to receive a threshold QRS width, and an output indicative of a detection of a wide QRS complex when the measured QRS width exceeds the threshold QRS width; and a wide-QRS indicator coupled to the wide-QRS detector, the wide-QRS indicator including an image generator configured to present a message window on the screen in response to the detection of the wide QRS complex, the message window displaying a message indicative of the detection of the wide QRS complex.
 2. The system of claim 1, further comprising a programming circuit coupled to the external telemetry circuit and the user interface, the programming circuit configured to program the implantable medical device, and the user interface comprises a programming input device configured to receive user input from a user, the user input related to programming of the implantable medical device.
 3. The system of claim 1, further comprising a surface ECG sensing circuit configured to sense a surface ECG signal using surface ECG electrodes, and wherein the signal input is programmable for receiving one of the surface ECG signal and a wireless ECG signal transmitted from the implantable medical device, the wireless ECG signal being a signal sensed by the implantable medical device using implantable electrodes.
 4. The system of claim 1, wherein the user interface comprises a threshold input device configured to receive the threshold QRS width from a user.
 5. The system of claim 4, wherein the threshold input device is configured to allow the user to type in the threshold QRS width.
 6. The system of claim 4, wherein the threshold input device is configured to allow the user to select from a plurality of predetermined threshold QRS widths.
 7. The system of claim 1, comprising an external device communicatively coupled to the implantable medical device via the telemetry, a remote device, and a telecommunication network coupled between the external device and the remote device.
 8. The system of claim 7, wherein the remote device comprises the screen.
 9. The system of claim 1, wherein the image generator is configured to cause a text message to be displayed in the message window, the text message directly indicative of the detection of the wide QRS complex.
 10. The system of claim 9, wherein the image generator is configured to cause the measured QRS width to be displayed in the message window.
 11. The system of claim 9, wherein the user interface comprises a printer, and the wide-QRS indicator comprises a message generator configured to produce a message indicative of the detection of the wide QRS complex to be printed by the printer.
 12. A method for operating an external system configured to communicate with an implantable medical device implanted in a patient, the method comprising: receiving an electrocardiogram (ECG) signal sensed from the patient; measuring a QRS width from the received ECG signal; detecting a wide QRS complex by comparing the measured QRS width to a threshold QRS width; and presenting a message window on a display screen of the external system in response to a detection of the wide QRS complex, the message window displaying a message indicative of the detection of the wide QRS complex.
 13. The method of claim 12, comprising sensing a surface ECG signal using surface ECG electrodes attached onto an exterior surface of the patient's skin, and wherein receiving the ECG signal comprises receiving the sensed surface ECG signal.
 14. The method of claim 12, comprising sensing a wireless ECG signal using the implantable medical device and implantable ECG electrodes implanted in the patient, and wherein receiving the ECG signal comprises receiving the sensed wireless ECG signal from the implantable medical device via telemetry.
 15. The method of claim 14, wherein sensing the wireless ECG signal comprises sensing the wireless ECG signal using subcutaneous electrodes attached to the implantable medical device.
 16. The method of claim 12, further comprising programming the implantable medical device to adjust one or more therapy parameters in response to the detection of the wide QRS complex.
 17. The method of claim 12, comprising receiving the threshold QRS width from a user using a user input device of the external system.
 18. The method of claim 12, comprising displaying a text message in the message window, the text message directly indicative of the detection of the wide QRS complex.
 19. The method of claim 18, comprising displaying the measured QRS width in the message window.
 20. The method of claim 18, comprising printing a message indicative of the detection of the wide QRS complex using a printer of the external system. 